1. Field of the Invention
The present application relates to a method and device for digitally upgrading textile.
2. Description of the Related Art
Roughly five production stages can be distinguished in the production of textiles. The fibre production, spinning of the fibres, the manufacture of cloth (for instance woven or knitted fabrics, tufted material or felt and non-woven materials), the upgrading of the cloth and the production or manufacture of end products. Textile upgrading is a totality of operations which have the purpose of giving textile the appearance and physical characteristics that are desired by the user. Textile upgrading comprises of, among other things, preparing, bleaching, optically whitening, colouring (painting and/or printing), coating and finishing a textile article.
The conventional process for upgrading textile is built up (FIG. 1) of a number of part-processes or upgrading steps, i.e. pre-treating the textile article (also referred to as the substrate), painting the substrate, coating the substrate, finishing the substrate and the post-treatment of the substrate.
A known technique for printing textile is the so-called template technique. Ink is herein applied to cut-out leaves or elements, the templates, with which desired patterns such as letters and symbols can be applied to the substrate. Another known technique for printing textile is the so-called flatbed press technique, wherein the printed image lies in one plane with the parts of the print mould not forming a printing area. An example hereof is a so-called offset print, wherein the printing process takes place indirectly. During the printing the print area is first transferred onto a rubber fabric tensioned round a cylinder and from there onto the material for printing. A further technique is screen-printing, wherein the substance for applying is applied through openings in the print template onto the textile for printing.
The above described techniques all relate to the upgrading step of printing a substrate, in particular textile, or, in other words, they relate to the application of a pattern of a coloured substance to the substrate.
As is already indicated in FIG. 1, painting of the substrate is another upgrading step. Painting is the application of a coloured chemical substance in a full plane, and then uniformly in one colour. Painting takes place at present by immersing the textile article in a paint bath, whereby the textile is provided on both sides with a coloured substance.
Another upgrading step is coating of textile. Coating of textile involves the application of an optionally (semi-)permeable thin layer to the textile to protect (and increase the durability of) the substrate. The usual techniques for applying a coating on solvent or water basis are the so-called knife-over-roller, the dip and the reverse roller coaters. A dispersion of a polymer substance in water is usually applied to the cloth and excess coating is then scraped off with a doctor knife.
A further upgrading step involves finishing of the textile. Finishing is also referred to as high-quality upgrading and involves changing the physical properties of the textile and/or the substances applied to the textile, with the object of changing and/or improving the properties of the substrate. Properties it is wished to achieve with finishing are, among others, softening of the surface of the substrate, making the substrate fireproof or flameproof, water-repellent and/or oil-repellent, non-creasing, shrink-proof, rot-proof, non-sliding, fold-retaining and/or antistatic. A technique frequently used for finishing is foularding (impregnating and pressing).
Each of the upgrading steps shown in FIG. 1 consists of a number of operations. Diverse treatments with diverse types of chemicals are required, depending on the nature of the substrate and desired end result. For the upgrading steps of printing, painting, coating and finishing four recurring steps can generally be distinguished which often take place in the same sequence. These treatments are referred to in the professional field as unit operations. These are the treatments of impregnation (i.e. application or introduction of chemicals), reaction/fixing (i.e. binding chemicals to the substrate), washing (i.e. removing excess chemicals and auxiliary chemicals) and drying.
One drawback of the usual methods of upgrading is that per upgrading step (painting, coating, finishing) two or more cycles of unit operations have to be carried out to achieve the desired result. Three or more cycles of unit operations are often necessary for coating, which entails a relatively high environmental impact, a long throughput time and relatively high production costs. Four or more cycles of unit operations are even required for painting. The traditional painting process has for instance the final operations of several rinses (washing and soaping) for rinsing out excess chemicals, such as for instance thickening agent. Rinsing results in the use of much water. Following on from the rinses is a drying process, usually consisting of a mechanical drying step using press-out rollers and/or vacuum systems followed by a thermal drying step, for instance using tenter-frames.
It is moreover usual at this moment to carry out the different upgrading steps of the textile in separate devices. This means that for instance the painting is performed in a number of paint baths specially suitable for the purpose, the printing and coating are carried out in separate printing devices and coating machines, while finishing is carried out by yet another device. Because the different operations are carried out individually in separate devices, the treating of the textile requires a relatively large area, usually spread over different room areas.
It is an object of the present invention to provide a method for upgrading, i.e. painting, coating and/or finishing, a substrate of textile where the above stated drawbacks and other drawbacks associated with the prior art are obviated.